Background: The visual and mental development of preterm infants improved after feeding them milk enriched with docosahexaenoic acid (DHA) in amounts matching the fetal accretion rate. Objective: The objective was to evaluate whether feeding preterm infants milk with a higher DHA content than that used in current practice influences language or behavior in early childhood. Design: This was a follow-up study in a subgroup of infants enrolled in the DINO (Docosahexaenoic acid for the Improvement in Neurodevelopmental Outcome) trial. In a double-blind randomized controlled trial, infants born at <33 wk of gestation were fed milk containing 1% of total fatty acids as DHA (higher-DHA group) or ≈0.3% DHA (control group) until reaching full-term equivalent age. The longer-term effects of the intervention on language, behavior, and temperament were measured by using the MacArthur Communicative Development Inventory (MCDI) at 26-mo corrected age, the Strengths and Difficulties Questionnaire (SDQ), and the Short Temperament Scale for Children (STSC) between 3- and 5-y corrected age. Results: Mean (±SD) MCDI scores did not differ significantly (adjusted P = 0.8) between the higher-DHA group (308 ± 179, n = 60) and the control group (316 ± 192, n = 67) per the Vocabulary Production subscale. Composite scores on the SDQ and STSC did not differ between the higher-DHA group and the control group [SDQ Total Difficulties: higher-DHA group (10.3 ± 6.0, n = 61), control group (9.5 ± 5.5, n = 64), adjusted P = 0.5; STSC score: higher-DHA group (3.1 ± 0.7, n = 61), control group (3.0 ± 0.7, n = 64), adjusted P = 0.3]. Conclusions: Feeding preterm infants milk containing 3 times the standard amount of DHA did not result in any clinically meaningful change to language development or behavior when assessed in early childhood. Whether longer-term effects of dietary DHA supplementation can be detected remains to be assessed. This trial was registered with the Australia and New Zealand Clinical Trial Registry at www.anzctr.org.au as 12606000327583.